1. Field of the Invention
This invention relates generally to a magnetic recording disk cartridge, and more specifically to a write protection device for such a cartridge.
2. Description of the Prior Art
Write protection devices have been used to prevent the loss of data on a magnetic recording disk by accidentally recording over the data. One such device is a breakaway flap covering an aperture in a magnetic disk cartridge manufactured by Sony Corporation. This flap prevents a spring loaded plunger switch from extending through the aperture and activating a circuit for recording. By breaking the flap away from the aperture, the write protection is lost and new data can be recorded on the disk. Such a device does not permit a user to choose a write protect mode of operation after the write enabling mode has been utilized.
An optical light sensor can be used to control a write enabling circuit. Light from a source on one side of a magnetic disk cartridge can pass through an aperature in the cartridge to activate the optical light sensor. Thus, the write enabling circuit can be controlled by blocking or opening the aperture.